Expressing things in terms of other things

I have a great love for expressing things in terms of other things. For example, you can express multiplication by any constant by a constant number of additions. You can express greater than or equal to (\(\ge\)) in terms of conjunction, less than, and addition. You can express disjunction in terms of negation and conjunction. Or how you can express minimum, maximum, and absolute difference in terms of proper subtraction, addition, and subtraction as seen here. Other pages related to this topic are here and here.

This stuff interests me because I want to know the minimal set of tools from which a thing can be constructed. Similarly, using Cantor's pairing function, you can encode a pair of numbers in a single number. This interest can be generalized to Turing-completeness, where we ask whether some small set of instructions is enough to express any computable function.